City staff are recommending that Ontario Place be listed on Toronto's heritage property register.

The proposal is contained in a new report set to make its way to the preservation board later this month before landing at council for a potential vote in mid-May. The recommendation comes as the province prepares to begin soliciting ideas for redevelopment of the site.

The sprawling waterfront attraction "remains a rare and intact Modernist expression of integrated architecture, engineering and landscape architecture that honours and incorporates the natural setting of Lake Ontario," staff writes.

"It was a remarkable and ambitious achievement of late twentieth century architecture, and holds an enduring influence in Toronto, the province and internationally," the report continues.

Since the vast majority of the site is owned by the province, the city does not have authority to formally designate Ontario Place as a heritage property. The property as a whole, however, can be listed on the city's heritage inventory.

The listing does not offer any legal protections under the Ontario Heritage Act and would serve mostly as a symbolic gesture that would signal that the city hopes to see elements of Ontario Place preserved.

Tamara Anson-Cartwright is program manager in planning, urban design and heritage at the city. She says that Ontario Place, with its geometric pods and iconic Cinesphere, is a rare surviving example of "post-Expo 67" Modernist architecture.

"I think everyone understands it to be this extraordinary place," she told CBC Toronto.

The city's report also emphasizes the design and cultural value of Trillium Park and William G. Davis Trail.

"I think one of the things I appreciated growing up in Toronto was that [Ontario Place] was a place that anyone could go to" and the introduction of Trillium Park in 2017 helped to restore that sense, Anson-Cartwright said.

'One more tool'

Listing the site on the city's heritage register was a key directive of the recently formed Ontario Place sub-committee.

Suzanne Kavanagh, a member of the grassroots group Ontario Place for All, said the listing would be "one more tool in the tool box" amid ongoing conversations about the site's future.

"The thing that we've been stressing all along is that when this was built by the Conservatives in 1971, it was meant to be a public park for everyone in Ontario. And to do anything to undo that would be a detriment to the province," she said.

Ontario's current Progressive Conservative government has indicated that it expects a major development on the sprawling 90-acre venue. It will begin accepting expressions of interest from developers and other stakeholder groups in the coming weeks.

Premier Doug Ford and Finance Minister Vic Fedeli have repeatedly said that nothing is "off the table" when it comes to future visions for Ontario Place.

The government fuelled further speculation about its intentions when it unveiled a $28.5-billion transit plan for the GTA last week, a plan that includes a new light rail line with its western terminus on the Ontario Place grounds.

While groups like Ontario Place for All have long advocated for better public transit to the venue, some opposed to the province's transit strategy argue that a light rail line to the site doesn't make much planning sense — unless, of course, there is some sort of major attraction in its future.

Though it shuttered attractions on the property in 2012, the previous Liberal government identified Ontario Place as a "cultural heritage landscape of provincial significance" two years later, the city staff report notes. A summary of that evaluation was posted online for several years. However, in January this year, the page was quietly removed from the website of the Ministry of Tourism, Culture and Sport (an archived version survives here).

Kavanagh said her group and the sub-committee will keep a close eye on any forthcoming expressions of interest that could compromise public access to Ontario Place, as well as any proposals that include long-term leases.